Our aim is to describe the relationship between the structure and function of key lymphocyte surface molecules emphasizing the modulating influence of membrane properties and interaction with the cytoskeleton. Our rationale is to analyze the dynamics of lymphocyte receptor movement, to explore the effects of modulation of this movement on growth control and mitogenesis, to analyze the structure of key molecules such as H-2 antigens and microglobulins and to use specially chosen lectins as tools and perturbants to explore the various interactions of those molecules. Specifically, our goals are: 1) to analyze the role of microtubules as positive and negative control elements in mitogenesis; 2) to determine primary structural features of H-2 antigens and beta2 microglobulins; 3) to analyze the 3D structure of beta2-microglobulin and its resemblance to immunoglobulin domains; 4) to characterize several key lectins in terms of their structure and functions as ligands; 5) to compare the properties of lymphocyte surfacemolecules with those of other tissues, emphasizing their role in development. The overall aim is to help understand the ontogeny and regulatory aspects of the immune response.